Tissue-removing catheter

ABSTRACT

A tissue-removing catheter for removing tissue in a body lumen includes an elongate body sized and shaped to be received in the body lumen. A handle is mounted at a proximal end portion of the catheter and is operable to cause rotation of the elongate body. A tissue-removing element is mounted on a distal end portion of the elongate body. The tissue-removing element is configured to remove the tissue as the tissue-removing element is rotated by the elongate body within the body lumen. A guidewire lumen extends through the elongate body from a distal end of the catheter to an intermediate location on the catheter spaced distally from the proximal end portion of the catheter. The guidewire lumen is configured to receive a guidewire such the catheter can be removed from the body lumen by pulling the catheter along the guidewire without removing the guidewire from the body lumen.

CROSS-REFERENCE TO RELATED APPLICATIONS

The present application claims the benefit of, and priority to, U.S.Provisional Application Ser. No. 62/500,867, which was filed May 3,2017, and U.S. Patent Application Ser. No. 62/500,879, which was filedMay 3, 2017, each of which is incorporated herein by reference in itsentirety for all purposes.

FIELD

The present disclosure generally relates to a tissue-removing catheter,and more particular, to a rapid exchange guidewire assembly for atissue-removing catheter.

BACKGROUND

Tissue-removing catheters are used to remove unwanted tissue in bodylumens. As an example, atherectomy catheters are used to remove materialfrom a blood vessel to open the blood vessel and improve blood flowthrough the vessel. This process can be used to prepare lesions within apatient's coronary artery to facilitate percutaneous coronaryangioplasty (PTCA) or stent delivery in patients with severely calcifiedcoronary artery lesions. Atherectomy catheters typically employ arotating element which is used to abrade or otherwise break up theunwanted tissue.

SUMMARY

In one aspect, a tissue-removing catheter for removing tissue in a bodylumen generally comprises an elongate body having an axis and proximaland distal end portions spaced apart from one another along the axis.The elongate body is sized and shaped to be received in the body lumen.A handle is mounted at a proximal end portion of the catheter and isoperable to cause rotation of the elongate body. A tissue-removingelement is mounted on the distal end portion of the elongate body. Thetissue-removing element is configured to remove the tissue as thetissue-removing element is rotated by the elongate body within the bodylumen. A guidewire lumen extends through the elongate body from a distalend of the catheter to an intermediate location on the catheter spaceddistally from the proximal end portion of the catheter. The guidewirelumen is configured to receive a guidewire such the catheter can beremoved from the body lumen by pulling the catheter along the guidewirewithout removing the guidewire from the body lumen.

In another aspect, a tissue-removing catheter for removing tissue in abody lumen generally comprises an elongate body having an axis andproximal and distal end portions spaced apart from one another along theaxis. The elongate body is rotatable and sized and shaped to be receivedin the body lumen. A tissue-removing element is mounted on the distalend portion of the elongate body. The tissue-removing element isconfigured to remove the tissue as the tissue-removing element isrotated by the elongate body within the body lumen. A guidewire lumenextends through the elongate body from a distal end of the catheter toan intermediate location on the catheter spaced distally from a proximalend of the catheter. The guidewire lumen is configured to receive aguidewire such the catheter can be removed from the body lumen bypulling the catheter along the guidewire without removing the guidewirefrom the body lumen.

In still another aspect, a method of removing tissue in a body lumengenerally comprises advancing a tissue-removing catheter over aguidewire in the body lumen to position a distal end of the catheteradjacent the tissue and a proximal end portion of the catheter outsideof the body lumen. The catheter comprises an elongate body, a tissueremoving element mounted on a distal end portion of the elongate body,and a guidewire lumen within the elongate body in which the guidewire isdisposed during the advancement of the catheter. The method furthercomprises rotating the elongate body and tissue-removing element of thecatheter to remove the tissue using a motor and a drive operativelyconnected to the elongate body and tissue-removing element. Andtransferring torque from the motor and drive to the elongate body andtissue-removing element using a gear assembly located at an intermediatelocation along the catheter.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 is an elevation of a catheter of the present disclosure;

FIG. 2 is an enlarged elevation of a distal end portion of the cathetershowing the catheter received in a guide catheter;

FIG. 3 is an enlarged fragmentary elevation of an intermediate portionof the catheter;

FIG. 4 is an enlarged fragmentary perspective view of the intermediateportion of the catheter received in the guide catheter and showing theguide catheter as transparent;

FIG. 5 is an enlarged fragmentary longitudinal vertical cross section ofthe intermediate portion of the catheter in FIG. 3;

FIG. 6 is an enlarged fragmentary longitudinal horizontal cross sectionof the intermediate portion of the catheter taken through line 6-6 inFIG. 3 with portions of a coil gear removed to show underlying detail;

FIG. 7 is an enlarged cross section taken through line 7-7 in FIG. 4;

FIG. 8 is an enlarged perspective view of a junction box of the catheterwith the junction box shown as transparent to show a gear assemblyinside the junction box;

FIG. 9 is a perspective view of the gear assembly;

FIG. 10 is an enlarged perspective view of a pinion gear of the gearassembly;

FIG. 11 is a cross section of the pinion gear;

FIG. 12 is an enlarged perspective view of a coil gear of the gearassembly;

FIG. 13 is a cross section of the coil gear;

FIG. 14 is an enlarged fragmentary longitudinal cross section of thedistal end portion of the catheter in FIG. 2;

FIG. 15 is a cross section taken through line 5-5 in FIG. 2;

FIG. 16 is a fragmentary elevation of an isolation liner of the catheterwith portions broken away to show internal detail;

FIG. 17 is an enlarged longitudinal cross section of a tissue-removingelement of the catheter;

FIG. 18 is a fragmentary perspective of a catheter of another embodimentshowing a housing of a junction box as transparent to show internaldetail;

FIG. 19 is an elevation of the catheter in FIG. 18;

FIG. 20 is a longitudinal vertical cross section of the catheter in FIG.19;

FIG. 21 is an enlarged perspective view of a pinion gear of the catheterin FIG. 18;

FIG. 22 is a cross section of the pinion gear in FIG. 21;

FIG. 23 is an enlarged perspective view of a coil gear of the catheterin FIG. 18; and

FIG. 24 is a cross section of the coil gear in FIG. 23.

Corresponding reference characters indicate corresponding partsthroughout the drawings.

DETAILED DESCRIPTION

Referring to the drawings, and in particular FIG. 1, a rotationaltissue-removing catheter for removing tissue in a body lumen isgenerally indicated at reference number 10. The illustrated catheter 10is a rotational atherectomy device suitable for removing (e.g.,abrading, cutting, excising, ablating, etc.) occlusive tissue (e.g.,embolic tissue, plaque tissue, atheroma, thrombolytic tissue, stenotictissue, hyperplastic tissue, neoplastic tissue, etc.) from a vessel wall(e.g., coronary arterial wall, etc.). The catheter 10 may be used tofacilitate percutaneous coronary angioplasty (PTCA) or the subsequentdelivery of a stent. Features of the disclosed embodiments may also besuitable for treating chronic total occlusion (CTO) of blood vessels,and stenoses of other body lumens and other hyperplastic and neoplasticconditions in other body lumens, such as the ureter, the biliary duct,respiratory passages, the pancreatic duct, the lymphatic duct, and thelike. Neoplastic cell growth will often occur as a result of a tumorsurrounding and intruding into a body lumen. Removal of such materialcan thus be beneficial to maintain patency of the body lumen.

The catheter 10 is sized for being received in a blood vessel of asubject. Thus, the catheter 10 may have a maximum size of 3, 4, 5, 6, 7,8, 9, 10, or 12 French (1, 1.3, 1.7, 2, 2.3, 2.7, 3, 3.3, or 4 mm) andmay have a working length of 20, 30, 40, 60, 80, 100, 120, 150, 180 or210 cm depending of the body lumen. While the remaining discussion isdirected toward a catheter for removing tissue in blood vessels, it willbe appreciated that the teachings of the present disclosure also applyto other types of tissue-removing catheters, including, but not limitedto, catheters for penetrating and/or removing tissue from a variety ofocclusive, stenotic, or hyperplastic material in a variety of bodylumens.

Referring to FIGS. 1-3, the catheter 10 comprises an elongate outerlayer 12 (broadly, an elongate body) disposed around an elongate innerliner 14. The outer layer 12 and inner liner 14 extend along a firstlongitudinal axis LA1 of the catheter from a junction box 15 to a distalend portion 18 of the catheter. The junction box 15 is located at anintermediate position along the catheter 10. In one embodiment, thejunction box 15 is disposed about 20 to about 30 cm from the distal endof the catheter 10. A tissue-removing element 20 is disposed on a distalend of the outer layer 12 and is configured for rotation to removetissue from a body lumen as will be explained in greater detail below. Asheath 22 (FIGS. 1 and 2) is disposed around the outer layer 12. Thecatheter 10 is sized and shaped for insertion into a body lumen of asubject. The sheath 22 isolates the body lumen from at least a portionof the outer layer 12 and inner liner 14. The sheath 22, outer layer 12,and inner liner 14 extend distally from the junction box 15. The innerliner 14 at least partially defines a guidewire lumen 24 for slidablyreceiving a guidewire 26 therein so that the catheter 10 can be advancedthrough the body lumen by traveling along the guidewire. The junctionbox 15 defines a guidewire port 39 which may also defines a portion ofthe guidewire lumen 24. The guidewire port 39 provides an exit locationfor the guidewire at an intermediate location on the catheter 10. Theguidewire 26 can be a standard 0.014 inch outer diameter guidewire.However, the junction box 15 allows for a shorter guidewire to be usedwith the catheter 10 because the guidewire exits the catheter 10 at theintermediate location on the catheter rather than extending along theentire working length of the catheter. In one embodiment, a guidewirehaving a length of less than about 200 cm (79 inches) may be used withthe catheter 10. In one embodiment, a guidewire having a length ofbetween about 150 cm (59 inches) and about 190 cm (75 inches) can beused. In certain embodiments, the inner liner 14 may have a lubriciousinner surface for sliding over the guidewire 26 (e.g., a lubricioussurface may be provided by a lubricious polymer layer or a lubriciouscoating). In the illustrated embodiment, the guidewire lumen 24 extendsfrom the junction box 15 through the distal end portion 18 of thecatheter 10 such that the guidewire 26 is extendable along only aportion of the working length of the catheter 10. In one embodiment, theoverall working length of the catheter 10 may be between about 135 cm(53 inches) and about 142 cm (56 inches).

The catheter 10 further comprises a handle 40 secured at a proximal endportion 16 of the catheter. The handle 40 supports an actuator 42 (e.g.,a lever, a button, a dial, a switch, or other device) configured forselectively actuating a motor 43 disposed in the handle to driverotation of a drive 48 extending from the motor to the junction box 15.The drive 48 may have a length of about 100 cm to space the junction box15 from the handle 40. The drive 48 may have other lengths withoutdeparting from the scope of the disclosure. In the illustratedembodiment the drive 48 is a coil shaft. A drive tube 27 encases thedrive 48 and extends from the handle 40 to the junction box 15 toisolate the body lumen from the rotating drive. The drive tube 27 anddrive 48 extend along a second longitudinal axis LA2 of the catheter 10from the handle 40 to the junction box 15. The second longitudinal axisLA2 extends parallel to and spaced from the first longitudinal axis LA1.As will be explained in greater detail below, the junction box 15transfers the torque of the drive 48 to the outer layer 12 for rotatingthe tissue-removing element 20 mounted at the distal end of the outerlayer. A perfusion port 46 may also be disposed at the proximal endportion 16 of the catheter 10. The perfusion port 46 communicates with aspace between a guide catheter 128 (FIGS. 4 and 7) and the drive tube 27for delivering fluid (e.g., saline) to cool the rotating components inthe junction box 15 and the rotating outer layer 12 during use.

It is understood that other suitable actuators, including but notlimited to touchscreen actuators, wireless control actuators, automatedactuators directed by a controller, etc., may be suitable to selectivelyactuate the motor in other embodiments. In some embodiments, a powersupply may come from a battery (not shown) contained within the handle40. In other embodiments, the power supply may come from an externalsource.

Referring to FIGS. 1, 3-5, and 8-13, the junction box 15 comprising ahousing 90 enclosing a gear assembly 92 for operatively connecting thedrive 48 to the outer layer 12. The gear assembly 92 in the junction box15 is configured to effectively transfer motor torque from the motor 43of up to about 13 mN.m. During the torque transfer, gears of the gearassembly 92 can rotate up to 10,000 RPMs and even up to 100,000 RPMs.The housing 90 comprises a rigid center portion 94 which generallysurrounds the gear assembly 92, and flexible proximal and distal endportions 96 which provide a strain relief function for the housing toalleviate tension applied to the proximal and distal ends of thejunction box 15 as the catheter 10 is bent during use. The rigid centerportion 94 comprises a casing 98 and first and second bearing holders100, 102 mounted on proximal and distal ends of the casing,respectively. The casing 98 may be formed from polyether ether ketone(PEEK).

The gear assembly 92 comprises a pinion gear 104 (broadly, a first gear)in mesh with a coil gear 106 (broadly, a second gear). The pinion gear104 is attached to the drive 48 such that rotation of the drive causesrotation of the pinion gear which in turn rotates the coil gear. Thecoil gear 106 is attached to the outer layer 12 such that rotation ofthe coil gear causes rotation of the outer layer. In particular, thepinion gear 104 comprises a proximal attachment portion 108, a distalend portion 110, and a middle gear portion 112. The proximal attachmentportion 108 includes a receptacle 114 that receives a distal end portionof the drive 48. The distal end portion of the drive 48 is fixed withinthe receptacle 114 to attach the drive to the pinion gear 104. In theillustrated embodiment the middle gear portion 112 includes ten (10)teeth 113. The middle gear portion 112 may have an outer diameter ofabout 0.8 mm (about 0.03 inches), and the teeth 113 of the middle gearportion may have a pitch diameter of about 0.6 mm (about 0.02 inches)and a pressure angle of about 20 degrees. Other dimensions of the piniongear 104 are also envisioned. A first pair of jewel bearings 116 arereceived around the proximal and distal end portions 108, 110,respectively, of the pinion gear 104 and facilitate rotation of thepinion gear in the junction box 15.

The coil gear 106 includes a distal attachment portion 118, a proximalportion 120, and a middle gear portion 122. The distal attachmentportion 118 is attached to the outer layer 12. In particular, a sectionof the distal attachment portion 118 is received in a proximal end ofthe outer layer 12 and fixedly attached thereto. In the illustratedembodiment, the middle gear portion 122 includes seventeen (17) teeth123. The middle gear portion 122 may have an outer diameter of about 1.3mm (about 0.05 inches). The teeth 123 of the middle gear portion 122 mayhave a pitch diameter of about 1.1 mm (about 0.04 inches) and a pressureangle of about 20 degrees. Other dimensions of the coil gear 106 arealso envisioned.

In one embodiment, the gear assembly 92 has a gear ratio of betweenabout 1 to 1 and about 2 to 1. In one embodiment, the gear assembly 92has a gear ratio of about 1.7 to 1. The coil gear 106 having a greaternumber of teeth than the pinion gear 104 means that the gear assembly 92will decrease the rotation speed of the coil gear 106 and outer layer 12as compared to the rotation speed of the drive 48 and pinion gear 104.However, the decreased rotation speed will result in an increased forceor torque output. Therefore, the coil gear 106, and thus the outer layer12 and tissue-removing element 20, will rotate with an increasedforce/torque as compared to the drive 48. This will allow thetissue-removing element 20 to better remove occlusive tissue in the bodylumen to separate the tissue from the wall of the body lumen.

A second pair of jewel bearings 124 are received around the distal andproximal end portions 118, 120, respectively, of the coil gear 106 andfacilitate rotation of the coil gear in the junction box 15. A passage126 extends through the coil gear 106 and receives a proximal endportion of the inner liner 14. The first bearing holder 100 is disposedaround the bearings 116, 124 around the proximal end portions 108, 120of the gears 104, 106, and the second bearing holder 102 is disposedaround the bearings 116, 124 around the distal end portions 110, 118 ofthe gears. The bearings 116, 124 can be made from bronze. However, othermaterials are also envisioned. For example, the bearings can also bemade from zirconia.

The housing 90 of the junction box 15 is sized such that the catheter 10can be received within a guide catheter 128 so a clearance (FIG. 7) isprovided on opposite lateral sides of the junction box to allow forsaline or contrast media perfusion between the guide catheter 128 andthe catheter 10. In particular, the center portion 94 of the housing 90has planar side surfaces which create clearance spaces 129 between thesides of the center portion and the curved inner wall of the guidecatheter 128. In one embodiment, the housing 90 is sized so that thecatheter 10 can be received in a 7F (about 2 mm) or smaller diameterguide catheter. In another embodiment, the housing 90 is sized so thatthe catheter 10 can be received in a 6F (about 1.8 mm) or smallerdiameter guide catheter.

Referring to FIGS. 6-8, a fluid port 130 may be provided in the drivetube 27 for introducing flushing/lubrication fluid into the gearassembly 92. In the illustrated embodiment, the port 130 is located inthe distal end portion of the drive tube 27 and is disposed inregistration with the proximal attachment portion 108 of the pinion gear104. Fluid that is introduced at the proximal end of the catheter 10 isdelivered through the guide catheter 128 and can be directed into thefluid port 130 and delivered to the middle gear portion 112 of thepinion gear 104 where rotation of the pinion gear transfers the fluidaround the pinion gear and to the middle gear portion 122 of the coilgear 106. Rotation of the coil gear, caused by rotation of the piniongear 104, moves the fluid around the coil gear 106 and transports thefluid to the distal attachment portion 118 of the coil gear where thefluid can be introduced into the space between the sheath 22 and theouter layer 12. Thus, the gear assembly 92 in the junction box 15 isconfigured to transport fluid from a proximal end of the junction box toa distal end of the junction box to cool the gear assembly 92 with thefluid. Additionally, by delivering fluid through the junction box 15fluid introduced at the proximal end of the junction box can betransported to the distal end of the junction box and pumped into thespace between the sheath 22 and the outer layer 12. Additionally, theasymmetrical configuration of the bearing holders 100, 102 facilitatethe flow of fluid from the proximal end of the junction box 15 to thedistal end.

Referring to FIGS. 5, 8, and 9, a sleeve 132 may also be disposed aroundthe proximal end portion 120 of the coil gear 106. The sleeve 132 isconfigured to reduce friction on the coil gear 106 created by a pushforce caused from advancing the catheter 10 through the body lumen. Thesleeve 132 may be made of graphite or some other low friction material.The sleeve 132 is configured to erode away in response to the push forceexperienced at the coil gear 106 during use of the catheter 10. Bylowering the friction force around the coil gear 106 the efficiency ofthe junction box 15 is maximized.

Referring to FIGS. 1-4, and 15, the outer sheath 22 comprises a tubularsleeve configured to isolate and protect a subject's arterial tissuewithin a body lumen from the rotating outer layer 12. The inner diameterof the sheath 22 is sized to provide clearance for the outer layer 12.The space between the sheath 22 and the outer layer 12 allows for theouter layer to rotate within the sheath and provides an area for salineperfusion between the sheath and outer layer. In one embodiment, thesheath 22 has an inner diameter of about 0.050 inches (1.27 mm) and anouter diameter of about 0.055 inches (1.4 mm). The sheath 22 can haveother dimensions without departing from the scope of the disclosure. Inone embodiment, the outer sheath 22 is made from polytetrafluorethylene(PTFE). Alternatively, the outer sheath 22 may comprise a multi-layerconstruction. For example, the outer sheath 22 may comprises an innerlayer of perfluoroalkox (PFA), a middle braided wire layer, and an outerlayer of Pebax.

Referring to FIGS. 1-4, 14, and 15, the outer layer 12 may comprise atubular stainless steel coil configured to transfer rotation and torquefrom the motor 43 and gear assembly 92 to the tissue-removing element20. Configuring the outer layer 12 as a coiled structure provides theouter layer with a flexibility that facilitates delivery of the catheter10 through the body lumen. Also, the coil configuration allows for therotation and torque of the outer layer 12 to be applied to thetissue-removing element 20 when the catheter 10 is traversed across acurved path. The stiffness of the outer layer 12 also impacts the easeat which the coil is traversed through the body lumen as well as thecoil's ability to effectively transfer torque to the tissue-removingelement 20. In one embodiment, the outer layer 12 is relatively stiffsuch that axial compression and extension of the coil is minimizedduring movement of the catheter 10 through a body lumen. The coilconfiguration of the outer layer 12 is also configured to expand itsinner diameter when the coil is rotated so that the outer layer remainsspaced from the inner liner 14 during operation of the catheter 10. Inone embodiment, the outer layer 12 has an inner diameter of about 0.023inches (0.6 mm) and an outer diameter of about 0.035 inches (0.9 mm).The outer layer 12 may have a single layer construction. For example,the outer layer may comprise a 7 filar (i.e., wire) coil with a layangle of about 30 degrees. Alternatively, the outer layer 12 could beconfigured from multiple layers without departing from the scope of thedisclosure. For example, the outer layer 12 may comprise a base coillayer and a jacket (e.g., Tecothane™) disposed over the base layer. Inone embodiment, the outer layer comprises a 15 filar coil with a layangle of about 45 degrees. The Tecothane™ jacket may be disposed overthe coil. Alternatively, the outer layer 12 may comprise a dual coillayer configuration which also includes an additional jacket layer overthe two coil layers. For example, the outer layer may comprise an innercoil layer comprising a 15 filar coil with a lay angle of about 45degrees, and an outer coil layer comprising a 19 filar coil with a layangle of about 10 degrees. Outer layer having other configurations arealso envisioned.

Referring to FIGS. 1-4 and 14-16, the inner liner 14 comprises amultiple layer tubular body configured to isolate the guidewire 26 fromthe coil gear 106, outer layer 12, and tissue-removing element 20. Theinner liner 14 is extendable through the junction box 15 to the distalend of the catheter 10. In one embodiment, the inner liner 14 is fixedlyattached to the junction box 15. The inner liner 14 has an innerdiameter that is sized to pass the guidewire 26. The inner liner 14protects the guide wire from being damaged by the rotation of the coilgear 106 and outer layer 12 by isolating the guidewire from therotatable coil gear and outer layer. The inner liner 14 also extendspast the tissue-removing element 20 to protect the guidewire 26 from therotating tissue-removing element. Thus, the inner liner 14 is configuredto prevent any contact between the guidewire 26 and the components ofthe catheter 10 that rotate around the guidewire. Therefore, anymetal-to-metal engagement is eliminated by the inner liner 14. Thisisolation of the coil gear 106, outer layer 12, and tissue-removingelement 20 from the guidewire 26 also ensures that the rotation of theouter layer and tissue-removing element is not transferred ortransmitted to the guidewire. As a result, a standard guidewire 26 canbe used with the catheter 10 because the guidewire does not have to beconfigured to withstand the torsional effects of the rotatingcomponents. Additionally, by extending through the tissue-removingelement 20 and past the distal end of the tissue-removing element, theinner liner 14 stabilizes the tissue-removing element by providing acentering axis for rotation of the tissue-removing element about theinner liner.

In the illustrated embodiment, the inner liner 14 comprises an innerPTFE layer 60 an intermediate braided layer 62 comprised of stainlesssteel, and an outer layer 64 of polyimide. The PTFE inner layer 60provides the inner liner 14 with a lubricous interior which aids in thepassing of the guidewire 26 though the inner liner. The braidedstainless steel intermediate layer 62 provides rigidity and strength tothe inner liner 14 so that the liner can withstand the torsional forcesexerted on the inner liner by the outer layer 12. In one embodiment, theintermediate layer 62 is formed from 304 stainless steel. The outerpolyimide layer 64 provides wear resistance as well as having alubricous quality which reduces friction between the inner liner 14 andthe outer layer 12. Additionally, a lubricious film, such as silicone,can be added to the inner liner 14 to reduce friction between the innerliner and the outer layer 12. In one embodiment, the inner liner 14 hasan inner diameter ID of about 0.016 inches (0.4 mm), an outer diameterOD of about 0.019 inches (0.5 mm), and a length of between about 7.9inches (about 200 mm) and about 15.7 inches (400 mm). The inner diameterID of the inner liner 14 provide clearance for the standard 0.014 inchguidewire 26. The outer diameter OD of the inner liner 14 providesclearance for the coil gear 106, outer layer 12, and tissue-removingelement 20. Having a space between the inner liner 14 and the outerlayer 12 reduces friction between the two components as well as allowsfor saline perfusion between the components.

In the illustrated embodiment, a marker band 66 (FIG. 2) is provided onan exterior surface of the distal end of the inner liner 14. The markerband 66 configures the tip of the inner liner 14 to be fluoroscopicallyvisible which allow a physician to verify the position of the linerduring a medical procedure. In this embodiment, the distal end of theinner liner 14 may be laser cut to provide a low profile tip. In oneembodiment, the marker band 66 comprises a strip of platinum iridium.

Referring to FIGS. 1, 2, and 17, the tissue-removing element 20 extendsalong the first longitudinal axis LA1 from a proximal end adjacent thedistal end portion of the outer layer 12 to an opposite distal end. Thetissue-removing element 20 is operatively connected to the motor 43 forbeing rotated by the motor. When the catheter 10 is inserted into thebody lumen and the motor 43 is activated to rotate the drive 48, whichrotates the gear assembly 92 which then transfers the motor torque tothe outer layer 12 thereby rotating the tissue-removing element 20, thetissue-removing element is configured to remove occlusive tissue in thebody lumen to separate the tissue from the wall of the body lumen. Anysuitable tissue-removing element for removing tissue in the body lumenas it is rotated may be used in one or more embodiments. In oneembodiment, the tissue-removing element 20 comprises an abrasive burrconfigured to abrade tissue in the body lumen when the motor 43 rotatesthe abrasive burr. The abrasive burr 20 may have an abrasive outersurface formed, for example, by a diamond grit coating, surface etching,or the like. In one embodiment, the tissue-removing element comprises astainless steel spheroid body with an exterior surface including 5 μm ofexposed diamond crystals. The tissue-removing element 20 may also beradiopaque to allow the tissue-removing element to be visible underfluoroscopy. In other embodiments, the tissue-removing element cancomprise one or more cutting elements having smooth or serrated cuttingedges, a macerator, a thrombectomy wire, etc.

A cavity 72 extends longitudinally through the tissue-removing element20 such that the tissue-removing element defines openings at itsproximal and distal ends. The cavity 72 receives a portion of the outerlayer 12 for mounting the tissue-removing element 20 to the outer layer.The cavity 72 includes a first diameter portion 74 extending from theproximal end of the tissue-removing element 20, a tapered diameterportion 76 extending from the first diameter portion toward the distalend of the tissue-removing element, and a second diameter portion 78extending from the tapered diameter portion to the distal end of thetissue-removing element. The diameters of the first and second diameterportions 74, 78 are constant along their lengths. In the illustratedembodiment, a diameter D1 of the first diameter portion 74 is largerthan a diameter D2 of the second diameter portion 78. In one embodiment,the diameter D1 of the first diameter portion 74 is about 0.035 inches(0.9 mm), and the diameter D2 of the second diameter portion 78 is about0.022 inches (0.56 mm). The tapered diameter portion 76 provides atransition between the first and second diameter portions 74, 78. Theouter layer 12 is received in the first diameter portion 74 and a distalend of the outer layer abuts the tapered diameter portion 76. Thetissue-removing element 20 can be fixedly attached to the distal end ofthe outer layer 12 by any suitable means. In one embodiment an adhesivebonds the tissue-removing element 20 to the outer layer 12. The innerliner 14 extends through the outer layer 12 and the second diameterportion 78 of the tissue-removing element 20. The second diameterportion 78 is sized to pass the inner liner 14 with a small clearance.The inner diameter D2 provides clearance between the tissue-removingelement 20 and inner liner 14 to reduce friction between the componentsand allow a space for saline perfusion. Accordingly, the tissue-removingelement 20 is shaped and arranged to extend around at least a portion ofthe outer layer 12 and inner liner 14 and thus provides a relativelycompact assembly for abrading tissue at the distal end portion of thecatheter 10.

The exterior surface of the tissue-removing element 20 includes aproximal segment 80, a middle segment 82, and a distal segment 84. Adiameter of the proximal segment 80 increases from the proximal end ofthe tissue-removing element 20 to the middle segment 82. The middlesegment has a constant diameter and extends from the proximal segment 80to the distal segment 84. The diameter of the distal segment 84 tapersfrom the middle segment 82 to the distal end of the tissue-removingelement 20. The tapered distal segment 84 provides the tissue-removingelement 20 with a general wedge shape configuration for wedging apartconstricted tissue passages as it simultaneously opens the passage byremoving tissue using the abrasive action of the tissue-removingelement. The distal end of the tissue-removing element 20 is alsorounded to provide the tissue-removing element with a blunt distal end.

Referring to FIGS. 1 and 2, to remove tissue in the body lumen of asubject, a practitioner inserts the guidewire 26 into the body lumen ofthe subject, to a location distal of the tissue that is to be removed.Subsequently, the practitioner inserts the proximal end portion of theguidewire 26 through the distal end of the guidewire lumen 24 of theinner liner 14 and through the junction box 15 so that the guidewireextends through the guidewire port 39 in the junction box to exit thecatheter 10. The guidewire port 39 allows the catheter 10 to be used ina rapid exchange and single operator exchange procedures. With thecatheter 10 loaded onto the guidewire 26, the practitioner advances thecatheter along the guidewire until the tissue-removing element 20 ispositioned proximal and adjacent the tissue. When the tissue-removingelement 20 is positioned proximal and adjacent the tissue, thepractitioner actuates the motor 43 using the actuator 42 to rotate thedrive 48, the gear assembly 92, the outer layer 12, and thetissue-removing element mounted on the outer layer. The tissue-removingelement 20 abrades (or otherwise removes) the tissue in the body lumenas it rotates. While the tissue-removing element 20 is rotating, thepractitioner may selectively move the catheter 10 distally along theguidewire 26 to abrade the tissue and, for example, increase the size ofthe passage through the body lumen. The practitioner may also move thecatheter 10 proximally along the guidewire 26, and may repetitively movethe components in distal and proximal directions to obtain aback-and-forth motion of the tissue-removing element 20 across thetissue. During the abrading process, the inner liner 14 isolates theguidewire 26 from the rotating coil gear 106, outer layer 12, andtissue-removing element 20 to protect the guidewire from being damagedby the rotating components. As such, the inner liner 14 is configured towithstand the torsional and frictional effects of the rotating coil gear106, outer layer 12, and tissue-removing element 20 without transferringthose effects to the guidewire 26. When the practitioner is finishedusing the catheter 10, the catheter can be removed from the body lumen.Because the guidewire lumen 24 is considerably shorter than the overalllength of the catheter 10, the catheter can be removed from the bodylumen in a rapid exchange or single operator exchange procedure withoutpulling the guidewire 26 out of the body lumen together with thecatheter because the length of the guidewire protruding from the subjectis longer than the length of the guidewire lumen 24 of the catheter.Thus, at least a portion of the guidewire 26 is exposed at all times andmay be grasped by the practitioner.

Referring to FIGS. 18-24, a catheter of another embodiment is generallyindicated at 10′. The catheter 10′ includes a junction box 15′ similarto the junction box 15 of the first embodiment. The junction box 15′comprises a housing 90′ enclosing a gear assembly 92′ for operativelyconnecting a drive 48′ to an outer layer 12′. The housing 90′ comprisesa center portion 94′ which generally surrounds the gear assembly 92′,and proximal and distal end portions 96′ which provide a strain relieffunction for the housing to alleviate tension applied to the proximaland distal ends of the junction box 15′ as the catheter 10′ is bentduring use.

The gear assembly 92 comprises a pinion gear 104′ in mesh with a coilgear 106′. The pinion gear 104′ is attached to the drive 48′ such thatrotation of the drive causes rotation of the pinion gear which in turnrotates the coil gear 106′. The coil gear is attached to the outer layer12′ such that rotation of the coil gear causes rotation of the outerlayer. The pinion gear 104′ comprises a proximal attachment portion108′, a distal end portion 110′, and a middle gear portion 112′. Thedrive 48′ is received in the proximal attachment portion 108′. The drive48′ is fixed within the proximal attachment portion 108′ to attach thedrive to the pinion gear 104′. In the illustrated embodiment, the middlegear portion 112′ includes eight (8) teeth 113′. The middle gear portion112′ may have an outer diameter of about 0.8 mm (about 0.03 inches), andthe teeth 113′ of the middle gear portion may have a pitch diameter ofabout 0.6 mm (about 0.02 inches) and a pressure angle of about 20degrees. Other dimensions of the pinion gear 104′ are also envisioned.

The coil gear 106′ includes an attachment portion 118′ and a gearportion 122′. A passage 126′ extends through the coil gear 106′ andreceives proximal end portions of the outer layer 12′ and inner liner14′. The attachment portion 118′ is attached to the proximal end of theouter layer 12′. In particular, the outer layer 12′ is received in theattachment portion 118′ of the coil gear 106′ and fixedly attachedthereto. In the illustrated embodiment, the gear portion 122′ includesfourteen (14) teeth 123′. The gear portion 122′ may have an outerdiameter of about 1.3 mm (about 0.05 inches). The teeth 123′ of the gearportion 122′ may have a pitch diameter of about 1.1 mm (about 0.04inches) and a pressure angle of about 20 degrees. Other dimensions ofthe coil gear 106′ are also envisioned. In one embodiment, the gearassembly 92′ has a gear ratio of between about 1 to 1 and about 2 to 1.In one embodiment, the gear assembly 92′ has a gear ratio of about 1.75to 1.

A first bearing 116′ is received around the proximal end portion 108′ ofthe pinion gear 104′ and the inner liner 14′. The first bearing 116′includes a first hole for receiving the proximal end portion 108′ of thepinion gear 104′, and a second hole for receiving the inner liner 14′. Asecond bearing 124′ is received around the distal end portions 110′,118′ of the pinion gear 104′ and coil gear 106′, respectively. Thesecond bearing 124′ includes a first hole for receiving the distal endportion 110′ of the pinion gear 104′, and a second hole for receivingthe distal end portion 118′ of the coil gear 106′. The bearings 116′,124′ can be made from bronze. However, other materials are alsoenvisioned. For example, the bearings 116′, 124′ can also be made fromzirconia.

When introducing elements of the present invention or the one or moreembodiment(s) thereof, the articles “a”, “an”, “the” and “said” areintended to mean that there are one or more of the elements. The terms“comprising”, “including” and “having” are intended to be inclusive andmean that there may be additional elements other than the listedelements.

As various changes could be made in the above apparatuses, systems, andmethods without departing from the scope of the invention, it isintended that all matter contained in the above description and shown inthe accompanying drawings shall be interpreted as illustrative and notin a limiting sense.

What is claimed is:
 1. A tissue-removing catheter for removing tissue ina body lumen, the tissue-removing catheter comprising: an elongate bodyhaving an axis and proximal and distal end portions spaced apart fromone another along the axis, the elongate body being sized and shaped tobe received in the body lumen; a handle mounted at a proximal endportion of the catheter and operable to cause rotation of the elongatebody; a tissue-removing element mounted on the distal end portion of theelongate body, the tissue-removing element being configured to removethe tissue as the tissue-removing element is rotated by the elongatebody within the body lumen; and a guidewire lumen extending through theelongate body from a distal end of the catheter to an intermediatelocation on the catheter spaced distally from the proximal end portionof the catheter, the guidewire lumen being configured to receive aguidewire such the catheter can be removed from the body lumen bypulling the catheter along the guidewire without removing the guidewirefrom the body lumen.
 2. A tissue-removing catheter as set forth in claim1, further comprising an inner liner received within the elongate body,the inner liner defining at least a portion of the guidewire lumen.
 3. Atissue-removing catheter as set forth in claim 2, further comprising ajunction box located at the intermediate location of the catheter, thejunction box defining a guidewire port for receiving the guidewire.
 4. Atissue-removing catheter as set forth in claim 3, further comprising agear assembly disposed in the junction box, the gear assembly engagingthe elongate body for rotating the elongate body.
 5. A tissue-removingcatheter as set forth in claim 4, further comprising a motor in thehandle and a drive extending distally from the motor to the junctionbox, the drive engaging the gear assembly for rotating the gear assemblyto rotate the elongate body and tissue-removing element mounted on theelongate body.
 6. A tissue-removing catheter as set forth in claim 5,wherein the drive defines a longitudinal axis that is parallel to andspaced apart from the longitudinal axis of the elongate body.
 7. Atissue-removing catheter as set forth in claim 5, further comprising adrive tube extend from the handle to the junction box, the drive tubedefining a fluid port for introducing fluid into the gear assembly.
 8. Atissue-removing catheter as set forth in claim 5, further comprising anactuator positioned on the handle and configured to selectively actuatethe motor to drive rotation of the elongate body and tissue-removingelement.
 9. A tissue-removing catheter as set forth in claim 3, whereinthe gear assembly comprises a first gear fixedly attached to the drive,and a second gear in mesh with the first gear and fixedly attached tothe elongate member.
 10. A tissue-removing catheter as set forth inclaim 9, wherein the second gear defines a passage for receiving theinner liner.
 11. A tissue-removing catheter as set forth in claim 2,wherein a distal end of the inner liner extend distally of thetissue-removing element.
 12. A tissue-removing catheter as set forth inclaim 1, wherein the tissue-removing element comprises an abrasive burr.13. A tissue-removing catheter for removing tissue in a body lumen, thetissue-removing catheter comprising: an elongate body having an axis andproximal and distal end portions spaced apart from one another along theaxis, the elongate body being rotatable and sized and shaped to bereceived in the body lumen; a tissue-removing element mounted on thedistal end portion of the elongate body, the tissue-removing elementbeing configured to remove the tissue as the tissue-removing element isrotated by the elongate body within the body lumen; and a guidewirelumen extending through the elongate body from a distal end of thecatheter to an intermediate location on the catheter spaced distallyfrom a proximal end of the catheter, the guidewire lumen beingconfigured to receive a guidewire such the catheter can be removed fromthe body lumen by pulling the catheter along the guidewire withoutremoving the guidewire from the body lumen.
 14. A tissue-removingcatheter as set forth in claim 13, further comprising an inner linerreceived within the elongate body, the inner liner defining at least aportion of the guidewire lumen.
 15. A tissue-removing catheter as setforth in claim 14, further comprising a junction box located at theintermediate location of the catheter, the junction box defining aguidewire port for receiving the guidewire.
 16. A tissue-removingcatheter as set forth in claim 15, further comprising a gear assemblydisposed in the junction box, the gear assembly engaging the elongatebody for rotating the elongate body.
 17. A tissue-removing catheter asset forth in claim 16, wherein the gear assembly comprises a gearfixedly attached to the elongate member, the gear defining a passage forreceiving the inner liner.
 18. A method of removing tissue in a bodylumen, the method comprising: advancing a tissue-removing catheter overa guidewire in the body lumen to position a distal end of the catheteradjacent the tissue and a proximal end portion of the catheter outsideof the body lumen, the catheter comprising an elongate body, a tissueremoving element mounted on a distal end portion of the elongate body,and a guidewire lumen within the elongate body in which the guidewire isdisposed during the advancement of the catheter; rotating the elongatebody and tissue-removing element of the catheter to remove the tissueusing a motor and a drive operatively connected to the elongate body andtissue-removing element; and transferring torque from the motor anddrive to the elongate body and tissue-removing element using a gearassembly located at an intermediate location along the catheter.
 19. Amethod of claim 18, further comprising extending the guidewire alongonly a portion of the catheter such that the guidewire exits thecatheter at the intermediate location.
 20. A method of claim 18, furthercomprising removing the catheter from the body lumen by pulling thecatheter along the guidewire without removing the guidewire from thebody lumen.